Coverage Checker

Coverage Checker checks .NET code coverage from the command line or from a .NET library. Use it to enforce line and branch coverage thresholds, analyse changed lines in pull requests, and filter coverage to the source files that matter for your project.

Features

• Coverage formats: Reads Cobertura, SonarQube, and OpenCover reports. Cobertura reports with multiple sources are supported.
• CLI and library APIs: Use the global .NET tool in CI, or reference the library from custom build tooling.
• Threshold enforcement: Fails the CLI when configured coverage targets are not met.
• Delta coverage: Checks only changed lines against a Git base branch or commit.
• File filtering: Includes or excludes source files with glob patterns.
• GitHub Actions output: Emits workflow annotations and job summaries when running in GitHub Actions.
• Integrated test workflow: Runs tests and checks the generated coverage with one run command.

Installation

Install the command line tool globally:

dotnet tool install --global CoverageChecker.CommandLine

Add the library package to a project:

dotnet add package CoverageChecker

CLI Usage

Coverage Checker has two CLI commands:

• check: analyses existing coverage files. This is the default command.
• run: runs a command, substitutes {output} with a coverage output directory, then analyses the generated files.

Check existing Cobertura, SonarQube, or OpenCover coverage files:

coveragechecker check --directory ./coverage --format Cobertura --glob-patterns "**/coverage.cobertura.xml" --line-threshold 80 --branch-threshold 70

Run tests and check the coverage they produce. The {output} token is replaced with a managed output directory:

coveragechecker run --command "dotnet test --collect 'XPlat Code Coverage' --results-directory {output}" --line-threshold 90

Run the test command from a solution or project subdirectory:

coveragechecker run --working-directory ./src/MySolution --command "dotnet test --collect 'XPlat Code Coverage' --results-directory {output}"

Check delta coverage against another branch:

coveragechecker --delta --delta-base origin/main --glob-patterns "**/coverage.cobertura.xml"

Require changed lines to meet a stricter threshold than overall coverage:

coveragechecker --delta --line-threshold 80 --delta-line-threshold 100

Fail when any Git-changed file with changed lines is absent from coverage data:

coveragechecker --delta --strict-delta --delta-base origin/main --glob-patterns "**/coverage.cobertura.xml"

Limit strict delta missing-file checks to the same file scope used for coverage analysis:

coveragechecker --delta --strict-delta --include "src/**/*.cs" --exclude "**/*.Generated.cs"

Limit analysis to selected source files:

coveragechecker --include "src/**" --exclude "**/Generated/**" --exclude "**/*Designer.cs"

See the command line README for the complete option reference.

GitHub Actions

Install the tool, run tests, then check the generated coverage report. Use fetch-depth: 0 when using --delta, because Coverage Checker needs Git history to compare against the base branch.

name: Build and Test

on:
  pull_request:
    branches: [ main ]

jobs:
  build-and-test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v6
        with:
          fetch-depth: 0

      - uses: actions/setup-dotnet@v5

      - name: Install Coverage Checker
        run: dotnet tool install --global CoverageChecker.CommandLine

      - name: Test
        run: dotnet test --collect "XPlat Code Coverage" --results-directory ./coverage

      - name: Check coverage
        run: >
          coveragechecker
          --format Cobertura
          --glob-patterns "./coverage/**/coverage.cobertura.xml"
          --line-threshold 80
          --branch-threshold 70
          --delta
          --delta-base origin/main

In GitHub Actions, threshold failures and coverage gaps are emitted as workflow annotations, and a coverage summary is added to the job summary.

Important Behavior

• If coverage files are found but there are no applicable lines after parsing or filtering, line coverage is unavailable and the CLI fails.
• If no branches are present, branch coverage is reported as N/A and the branch threshold does not fail.
• Delta coverage uses --delta-line-threshold and --delta-branch-threshold when provided. If either delta threshold is omitted, it defaults to the corresponding overall threshold.
• For delta coverage, changed lines in files that appear in the coverage data must also be present as covered or uncovered line entries. If changed coverage files are found but none of their changed lines match the coverage data, the CLI fails.
• By default, delta coverage ignores Git-changed files that are completely absent from coverage data. This keeps docs and config-only changes from failing existing workflows.
• Use --strict-delta with --delta to fail when any Git-changed file with changed lines is absent from coverage data. When --include or --exclude is provided, the strict missing-file check respects that same scope. Otherwise, strict delta applies to every file reported by Git with changed line numbers without distinguishing source from non-source files.
• Delta coverage and rename detection require Git on the system PATH.
• Cobertura, SonarQube, and OpenCover reports are supported. Cobertura reports with multiple source roots are supported.

Library Usage

Use CoverageAnalyser when you need coverage metrics inside custom .NET tooling:

using CoverageChecker;

CoverageAnalyserOptions options = new()
{
    CoverageFormat = CoverageFormat.Auto,
    Directory = "./coverage",
    GlobPatterns = ["**/coverage.cobertura.xml"]
};

CoverageAnalyser analyser = new(options);
Coverage coverage = analyser.AnalyseCoverage();

double lineCoverage = coverage.CalculateOverallCoverage(CoverageType.Line);

Package-specific READMEs contain the full CLI option reference and detailed library object model:

• Coverage Checker Command Line Tool
• Coverage Checker Library

Contributions

Contributions are welcome! Read the contributing guide to get started.

License

This project is licensed under the MIT License. See the LICENSE for details.